The present invention relates to an electrical connector, and particularly to an electrical connector for mounting an IC module to a circuit board and preventing misalignment between the IC module and the circuit board.
As the demand for high-speed notebook computer increases, IC modules are accordingly designed to fulfill the need. Conventional connectors for reliably connecting an IC module to a circuit board and for ensuring stable signal transmission are disclosed in Taiwan Patent Application Nos. 86100198 and 86207996.
Referring to FIGS. 1A to 1C, a contact 81 of a conventional connector for electrically connecting an IC module to a circuit board 9 generally comprises a fixing portion 811 and a soldering portion 812. A pair of engaging portions 813 is formed on opposite edges of the contact 81 for engaging with inner surfaces of a corresponding passageway 821 of a housing 82 thereby securing the pin 81 to the housing 82. To solder the contact 81 to a corresponding solder pad 91 formed on the circuit board 9, a solder ball 92 is attached to the solder portion 812 of the contact 81. The solder ball 92 is attached on the corresponding solder pad 91 and melted to engage with the solder pad 91 by a heating process. Thus, the IC module is electrically connected with the circuit board 9.
However, the thermal expansion coefficient of the housing 82 is different from that of the circuit board 9. Thus, when thermal expansion occurs during the heating process, the contact 81 may be improperly soldered to the solder pad 91 (FIG. 1C). Therefore, signal transmission between the contact 81 and the circuit board 9 is unreliable. Furthermore, if the contact 81 is soldered to the solder pad 91 at an ideal position (FIG. 1B), heat is generated while the contact 81 and the circuit board 9 are in operation thereby causing the connector and the circuit board 9 to expand and causing misalignment between the contacts 81 and the solder pads 9. Thus, reliable connection between the contacts 81 and the circuit board 9 is not provided.